Improvement in screw-cutting tools for metal-lathes



l. H. HASKINS & D. B. DENIS UN Screw-Cutting Tools for Metal-LathesL N0.145,450 PatentedJan.13,1874.

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UNITED STArEs PATENT OFFICE.

JAMES H. HASKINS AND DANIEL B. DENISON, OF GROTON, CONNECTICUT.

IMPROVEMENT IN SCREW-CUTTING TOOLS FOR METAL-LATHES.

Specification forming part of Letters Patent No. 146,450, dated January 13, 1874 application filed October 28, 1873.

To all whom it may concern:

Be it known that we, JAMES H. HASKINS and DANIEL B. DENISON, of the town of Groton, county of New London, State of Connecticut, have invented certain Improvements in Thread-Cutting Tools, as used in a lathe or lathes, of which the following is a specification:

This our invention consists in the use, application, and combination of two movable adj ustable cutters, fashioned and shaped, as to the cutting-edge thereof, according to the thread to be cut, (with one beveled side, to give clearance, in the case of cutters designed to cut a square thread,) so set and arranged in the holder that they shall be upon. and present their cutting-edges to opposite sides of the bar upon which the thread is to be cut. The object of our invention is, with one holder one tool-post, and one carriage, by moving the carriage as the lathe is reversed, to cut a thread as well on the backward motion of the lathe as on the forward motion.

Figure 1 is a side view of a holder embodyin g our invention. Fig. 2 is a vertical view of the same.

i A A a A A are cutters of best cast-steel. In Fig. 1, A a is the cutter which cuts the thread on the forward motion of the lathe, as does the cutter in ordinary use. A is the cutter which operates on backward motion of the lathe. These cutters are the shape used in cutting theV-shaped thread, so called. A and A are cutters for cutting the square 7 thread. 13 is the holder, through which are cut the slots E E for the reception of the cutters A and A a. G G are two setscrews, by

means of which the cutters are held in place in the slots E E. D D are eight gib-screws,which adjust the cutters to the required pitch. F is the gib.

The bar upon which the thread is to be cut is put in the lathe. The holder B is adjusted in the tool-post of the slide-rest. The cutters A and A on having been set to any required pitch, so that the cutter A a. strikes the bar at or toward the dead-center end of the lathe, or the end opposite where thepower is applied, and the lathe then being put in motion, the thread is cut on the baras the carriage traverses the distance to be out. When the carriage reaches the end of the out, the lathe is reversed. The

cutterA a is moved back from the bar by means of the adjusting-screw and serewhandleof the slide-rest. The cutter A is, bythis motion,

brought to bear upon the oppositeside of the substantially as and for the purposes set forth.

JAMES H. HASKINS. DANIEL B. DENISON.

Witnesses R. LATHAM MILLER, FRED. A. HOLMES. 

